Editor's Note: This is the first of six in the New York Times' series about the deadly avalanche at Stevens Pass in Washington. The series features professional skiier and part-time Santa Cruz resident Elyse Saugstad, who survived the ordeal. The series will appear every Friday in the Sports section, or can be viewed in its entirety online at www.santacruzsentinel.com

The snow burst through the trees with no warning but a last-second whoosh of sound, a two-story wall of white and Chris Rudolph's piercing cry: "Avalanche! Elyse!"

The very thing the 16 skiers and snowboarders had sought -- fresh, soft snow -- instantly became the enemy. Somewhere above, a pristine meadow cracked in the shape of a lightning bolt, slicing a slab nearly 200 feet across and 3 feet deep. Gravity did the rest.

Snow shattered and spilled down the slope. Within seconds, the avalanche was the size of more than a thousand cars barreling down the mountain and weighed millions of pounds. Moving about 70 miles per hour, it crashed through the sturdy old-growth trees, snapping their limbs and shredding bark from their trunks.

The avalanche, in Washington's Cascades in February, slid past some trees and rocks, like ocean swells around a ship's prow. Others it captured and added to its violent load.

The slope of the terrain, shaped like a funnel, squeezed the growing swell of churning snow into a steep, twisting gorge. It moved in surges, like a roller coaster on a series of drops and high-banked turns. It accelerated as the slope steepened and the weight of the slide pushed from behind. It slithered through shallower pitches. The energy raised the temperature of the snow a couple of degrees, and the friction carved striations high in the icy sides of the canyon walls.

Elyse Saugstad, a professional skier, wore a backpack equipped with an air bag, a relatively new and expensive part of the arsenal that backcountry users increasingly carry to ease their minds and increase survival odds in case of an avalanche. About to be overtaken, she pulled a cord near her chest. She was knocked down before she knew if the canister of compressed air inflated winged pillows behind her head.

She had no control of her body as she tumbled downhill. She did not know up from down. It was not unlike being cartwheeled in a relentlessly crashing wave. But snow does not recede. It swallows its victims. It does not spit them out.

Snow filled her mouth. She caromed off things she never saw, tumbling through a cluttered canyon like a steel marble falling through pins in a pachinko machine.

At first she thought she would be embarrassed that she had deployed her air bag, that the other expert skiers she was with, more than a dozen of them, would have a good laugh at her panicked overreaction. Seconds later, tumbling uncontrollably inside a ribbon of speeding snow, she was sure this was how she was going to die.

Moving, roiling snow turns into something closer to liquid, thick like lava. But when it stops, it instantly freezes solid. The laws of physics and chemistry transform a meadow of fine powder into a wreckage of icy chunks. Saugstad's pinwheeling body would freeze into whatever position it was in the moment the snow stopped.

After about a minute, the creek bed vomited the debris into a gently sloped meadow. Saugstad felt the snow slow and tried to keep her hands in front of her. She knew from avalanche safety courses that outstretched hands might puncture the ice surface and alert rescuers. She knew that if victims ended up buried under the snow, cupped hands in front of the face could provide a small pocket of air for the mouth and nose. Without it, the first breaths could create a suffocating ice mask.

The avalanche spread and stopped, locking everything it carried into an icy cocoon. It was now a jagged, virtually impenetrable pile of ice, longer than a football field and nearly as wide. As if newly plowed, it rose in rugged contrast to the surrounding fields of undisturbed snow, 20 feet tall in spots.

Saugstad was mummified. She was on her back, her head pointed downhill. Her goggles were off. Her nose ring had been ripped away. She felt the crushing weight of snow on her chest. She could not move her legs. One boot still had a ski attached to it. She could not lift her head because it was locked into the ice.

But she could see the sky. Her face was covered only with loose snow. Her hands, too, stuck out of the snow, one still covered by a pink mitten.

Using her hands like windshield wipers, she tried to flick snow away from her mouth. When she clawed at her chest and neck, the crumbs maddeningly slid back onto her face. She grew claustrophobic.

Breathe easy, she told herself. Do not panic. Help will come. She stared at the low, gray clouds. She had not noticed the noise as she hurtled down the mountain. Now, she was suddenly struck by the silence.

Tunnel Creek

The Cascades are among the craggiest of American mountain ranges, roughly cut, as if carved with a chain saw. In summer, the gray peaks are sprinkled with glaciers. In winter, they are smothered in some of North America's deepest snowpack.

The top of Cowboy Mountain, about 75 miles east of Seattle, rises to 5,853 feet -- about half the height of the tallest Cascades, but higher than its nearest neighbors, enough to provide 360-degree views. It feels more like a long fin than a summit, a few feet wide in parts. Locals call it Cowboy Ridge.

To one side, down steep chutes, is Stevens Pass ski area, which receives about 400,000 visitors each winter. To the other, outside the ski area's boundary to what is considered the back of Cowboy Mountain, is an unmonitored play area of reliably deep snow, a "powder stash," known as Tunnel Creek.

It is a term with broad meaning. The name is derived from the Cascade Tunnel, originally a 2.6-mile railroad tube completed in 1900 that connected the east and west sides of the Cascades. In late February 1910, ceaseless snowstorms over several days marooned two passenger trains just outside the tunnel's west portal. Before the tracks could be cleared, the trains were buried by what still stands as the nation's deadliest avalanche. It killed 96 people.

Bodies were extricated and wrapped in blankets from the Great Northern Railway, then hauled away on sleds. Some were not found until the snow melted many months later.

To skiers and snowboarders today, Tunnel Creek is a serendipitous junction of place and powder. It features nearly 3,000 vertical feet -- a rarely matched descent -- of open meadows framed by thick stands of trees. Steep gullies drain each spring's runoff to the valley floor and into a small, short gorge called Tunnel Creek.

The area has all of the alluring qualities of the backcountry -- fresh snow, expert terrain and relative solitude -- but few of the customary inconveniences. Reaching Tunnel Creek from Stevens Pass ski area requires a ride of just more than five minutes up SkyLine Express, a high-speed four-person chairlift, followed by a shorter ride up Seventh Heaven, a steep two-person lift. Slip through the open boundary gate, with its "continue at your own risk" warning signs, and hike 10 minutes to the top of Cowboy Mountain.

When snow conditions are right, the preferred method of descent used by those experienced in Tunnel Creek, based on the shared wisdom passed over generations, is to hopscotch down the mountain through a series of long meadows. Weave down the first meadow, maybe punctuate the run with a jump off a rock outcropping near the bottom, then veer hard left, up and out of the narrowing gully and into the next open glade.

Another powder-filled drop ends with another hard left, into a meadow that leads to the valley floor.

Tunnel Creek is, in the vernacular of locals, a "hippie pow run" -- breezy and unobstructed, the kind that makes skiers giggle in glee as they descend through a billowing cloud of their own soft powder and emerge at the bottom coated in white frosting.

But powder and people are key ingredients for avalanches. And the worry among avalanche forecasters, snow-science experts and search-and-rescue leaders is that the number of fatalities -- roughly 200 around the world each year -- will keep rising as the rush to the backcountry continues among skiers, snowboarders, climbers and snowmobilers.

The backcountry represents the fastest-growing segment of the ski industry. More than ever, people are looking for fresh descents accessible by helicopters, hiking or even the simple ride up a chairlift.

Before 1980, it was unusual to have more than 10 avalanche deaths in the United States each winter. There were 34 last season, including 20 skiers and snowboarders. Eight victims were skiing out of bounds, legally, with a lift ticket. And many of the dead were backcountry experts intimate with the terrain that killed them.

"It's a cultural shift, where more skiers are going farther, faster, bigger," said John Stifter, the editor of Powder magazine, who was a part of the group at Tunnel Creek in February. "Which is tending to push your pro skiers or other experienced, elite-level backcountry skiers that much farther, faster and bigger, to the point where there's no margin for error."

No one knows how many avalanches occur. Most naturally triggered slides are never seen. Those set off by humans are rarely reported unless they cause fatalities or property damage.

But avalanches occur in Tunnel Creek regularly. Its slopes, mostly from 40 to 45 degrees, are optimal for avalanches -- flat enough to hold deep reservoirs of snow, yet steep enough for the snow to slide long distances when prompted. The long elevation drop means snow can be fluffy at the top and slushy at the bottom. Temperatures, wind and precipitation change quickly, and something as welcome as a burst of sunshine can alter the crystallized bonds deep inside the snow. And because Tunnel Creek is outside the ski area, it is not patrolled or specifically assessed for danger.

In March 2011, a University of Washington student was caught in an avalanche in Tunnel Creek. Having been carried into a stand of trees, he was unburied by friends within minutes and found dead. Three others were partially buried about an hour later when the ski patrol's arrival set off a second avalanche.

Many of the most experienced locals view Tunnel Creek with a mix of awe and fear.

"I've always been a naysayer of Tunnel Creek," the snowboarder Tim Wesley said. "I've seen a big avalanche back there before. It has about 2,600 vertical feet. Not typical. The snow changes a lot in that distance. That's the reason I always have a second thought about Tunnel Creek. In Washington, there's a saying: If you don't like the weather, wait five minutes. And it's true. You'll be on the chair and it'll be freezing, and then all of a sudden there's a warm breeze that smells like the ocean."

Even those who are not leery of Tunnel Creek on the best days heed the pass-it-on warning of the experienced: stay left.

To head straight down to the bottom is to enter what experts call a terrain trap: a funnel of trouble and clumsy skiing, clogged with trees and rocks and confined by high walls. Few go that way intentionally.

Chris Rudolph, the effervescent 30-year-old marketing manager for Stevens Pass, knew the preferred route down. Tunnel Creek was his favorite at-work diversion. Earlier that weekend, he mentioned plans for a field trip to Tunnel Creek to a select group of high-powered guests and close friends.

The operations manager for Stevens Pass agreed to pick up the group in one of the ski area's trucks at the end of its descent. From the bottom of Tunnel Creek, it is about a half-mile trek through deep snow to U.S. 2, then a four-mile ride back to Stevens Pass.

At 11:32 a.m. on Sunday, Feb. 19, heading up the mountain, Rudolph sent a text message to the operations manager.

"A big posse," Rudolph wrote.

A Plan in Motion

Like many ideas that sound good at the time, skiing Tunnel Creek was an idea hatched in a bar.

It was Saturday, Feb. 18, the afternoon light fading to dusk. Outside the Foggy Goggle, a bar at the base of the ski area, the snow continued to fall, roughly an inch an hour. By morning, there would be 32 inches of fresh snow at Stevens Pass, 21 of them in a 24-hour period of Saturday and Saturday night.

That was cause for celebration. It had been more than two weeks since the last decent snowfall. Finally, the tired layer of hard, crusty snow was gone, buried deep under powder.

Rudolph promoted Stevens Pass with restless zeal. In seven years there, he helped turn a relatively small, roadside ski area into a hip destination.

He unabashedly courted ski journalists and filmmakers to take a look. They, in turn, gave Stevens Pass star turns in magazines and popular ski movies, raising the area's cool quotient.

Rudolph was the oldest of three children raised in Lafayette by outdoors-minded parents. The young family pulled a pop-up Coleman camper around the West and skied at the areas around Lake Tahoe.

Rudolph peppered his language with words like "rad" and "stoked." But he was no simple-minded ski bum. He was an Eagle Scout with a marketing degree. When he applied at Stevens Pass years earlier, he sent a video of himself speaking, skiing and mountain biking. He included a bag of popcorn for the viewer. He got the job.

Tunnel Creek was where he took special guests. And it is where he wanted to take the tangled assortment of high-caliber skiers and industry insiders who, as if carried by the latest storm, had blown into Stevens Pass that weekend.

Many of them happened into the Foggy Goggle on Saturday night.

Among them were professional skiers like Saugstad, 33, a former champion of the Freeride World Tour. There were reporters and editors from Powder magazine and ESPN. There were executives from ski equipment and apparel companies. There were Stevens Pass regulars, some with broad reputations in the niche world of skiing, glad to spend time with the assortment of guests.

"It was a very, very deep, heavy, powerful, strong group of pro skiers and ski industry people," said Keith Carlsen, a photographer and former editor of Powder.

Rudolph was the connecting thread. Some visitors, like Saugstad, were at Stevens Pass for a promotional event aimed at expert female skiers, sponsored by Salomon, the ski equipment maker.

Powder had come to spotlight Stevens Pass for a feature article on night skiing. When the magazine's editor, John Stifter, arrived by train to Leavenworth two days earlier, he found Rudolph's car waiting for him. Inside were keys to the car, keys to a slope-side cabin and two Pabst Blue Ribbons in the cup holders.

At the bar, Rudolph mentioned an idea to a few people: Tunnel Creek on Sunday. Invitations traveled in whispers and text messages, through a knot of friendships and slight acquaintances. Meet at the fire pit, on the stone deck at Granite Peaks Lodge, at 11.

Rudolph and those with the Salomon event left for dinner in Leavenworth. Stifter, 29, and Carlsen, 38, headed outside to work on their article for Powder.

"I skied just off the trail, not out of bounds, but in the ski resort, to shoot some of these night shots I took," Carlsen said. "And in tree wells I was, like, neck deep -- easily nipple deep, wading around in snow, trying to get my angle. There was so much new snow."

With the daytime crowds gone, the nighttime atmosphere was festive and the faces were familiar. Families played in the deepening snow. More serious skiers and snowboarders sought the freshest powder.

There are no public accommodations at Stevens Pass, only a parking lot available to a few dozen campers and recreational vehicles. As the evening wound down, several of those with loose plans to ski Tunnel Creek the next morning huddled in the R.V. lot around a fire. Carlsen continued taking photographs. Stifter and others ducked inside one camper to watch homemade videos of others skiing Tunnel Creek over the past couple of decades.